In the latest Mission: Impossible film, Tom Cruise’s character, Ethan Hunt, wows his team of special agents with a display of all the tech-laden new gear they’ll have for their next assignment, including a levitation suit. But he saves the best for last. “Wait until you see the car,” a smiling Cruise says. The reference is to the i8 concept, a next-generation supercar from BMW , which helps Cruise and co-star Paula Patton race through Mumbai traffic. The car’s appearance highlights the brand’s return to Hollywood after a hiatus of more than a decade. The sponsorship of Mission: Impossible-Ghost Protocol , opening in U.S. IMAX theaters on Dec. 16 and nationwide on Dec. 21, comes at the expense of Volkswagen’s Audi brand, which aims to topple BMW as the luxury car leader by 2015. Propaganda GEM, the Hollywood product placement agency that helped Audi boost its image with hig...